Re: [PATCH V7 1/1] perf tool:perf diff support for different binaries

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Thu, Feb 26, 2015 at 12:34:04PM -0800, Andi Kleen escreveu:
> > Having a nice explanation of the problem helps, as my first reaction to
> > this patch was: "What? This is what this tool is supposed to do, to
> > compare two versions of a binary, one that is being developed from the
> > same source, the other with slight modifications, etc", while the
> > description of the patch made it look as this was a feature that was now
> > being introduced.
> 
> AFAIK it was actually to compare multiple runs of the same binary
> with different setups: e.g. varying number of threads.
> 
> However in the Linux kernel development world it turns out comparing
> multiple similar binaries is much more useful.

Surely I am getting old and forgetting things, but when I wrote it, my
intent was to do:

vi a.c
build it
perf record a
vi a.c # change it
build it
perf record a
perf diff

And see if what I did while vi'ing it matched what I thought it would.

- Arnaldo